enzymes newest Flashcards
(41 cards)
1
Q
catalyst definition
A
a substance that speeds up the rate of chemical reaction without itslef being chemically changed at the end of the reaction
2
Q
enzymes are
A
biological catalysts
- catalyse/speed up the rate of chemical reaction
3
Q
activation energy
A
- energy needed to start a chemical reaction
4
Q
enzymes lower activation energy
A
enzymes lower activation energy ->speed up chemical reaction
5
Q
energy required with and without enzymes
A
- without enzymes, activation energy is lower, which thus speeds up the process
6
Q
why enzymes break down molecules into smaller ones
A
- soluble in water
- small enough to diffuse through the cell membrane
7
Q
hydrolase (enzymes)
A
amylase
maltase
protease
lipase
carbohydrase
8
Q
amylase
A
- digests starch to maltose
- hydrolysis of glycosidic bonds
9
Q
maltase
A
- digests maltose to glucose
- hydrolysis of glycosidic bonds
10
Q
protease
A
- digests proteins to polypeptides, then amino acids
- hydrolysis of peptide bonds
11
Q
lipase
A
- digests fats into fatty acids then glycerol
- hydrolysis of ester bonds
12
Q
enzymes types (i and e)
A
intracellular
extracellular
13
Q
intracellular enzymes
A
- in nucleus, attached to plasma membrane
- inside membranous orangenelles
14
Q
extracellular enzymes
A
- produced int he cell but packaged to be secreted from the cell and work externally
15
Q
substrate definition
A
chemical which an enzymes works on
- eg: protein
16
Q
enzyme + substrate (E+S)
A
- binding of substrate to active site of the enzymes
- brief and reversible
- no covalent bond formation
- proximity of enzyme with substrate increases chances of reaction
17
Q
enzyme-substrate complex (ES)
A
- enzymes and substrates are in random motion
- substrate collide with active site of enzyme at specific orientation with sufficient energy to form ES complex
- the faster the speed of the reaction, the more ES complexes are formed
18
Q
enzyme-product complex (EP)
A
- ES complex is converted to EP complex
19
Q
enzyme and product (E+P)
A
- EP complex dissociates to form enzyme and product
- enzyme remains unchanged at the end of reaction and can be used to catalyse other substrate molecules
20
Q
enzymes pathway
A
- binding of substrate to enzyme forming an enzyme-substrate complex
- conversion of ES to EP
- release of P from EP
- E+S and EP is in equilibrium because when the collision partners form an activated complex, they might not go on and form products. instead, the complex may fall apart back to the reactants
21
Q
metabolism
A
anabolism
catabolism
22
Q
anabolism
A
- building up complex substances
- using simple molecules to synthesise complex substances with energy harnessed from catabolic activities
23
Q
catabolism
A
- breaking down complex substances into small simple molecules, generating energy fro the cell
24
Q
metabolic pathway
A
- series of enzyme catalysed reaction in which product from one reaction is the substrate for the next
- enzyme catalyses a particular chemical reaction—enzyme is unchanged
- pathway can occur at the same time
- using different enzymes to catalyse each step enables the cell to have more than one mechanism
25
enzymes properties (7)
1. globular proteins
2. coded for by DNA
3. highly efficient
4. highly specific
5. catalysed reaction is reversible
6. affected by multiple factors
7. increases rate of reaction by decreasing the activation energy
26
property one enzymes
enzymes are globular proteins
- soluble in water due to hydrophilic R groups of amino acid on exterior surface
- involved in metabolic reaction
27
property two enzyme
enzymes are coded for by DNA
- genes code for proteins
- cells which do not have a gene which codes for a specific enzyme will not be able to produce that enzyme
28
property three enzyme
enzymes are highly efficient
- small amount of enzymes bring the change of large amount of substrate
-> enzymes remain unchanged in the reaction they catalyse
29
property four enzyme
enzymes are highly specific
- catalyse a single reaction
- specific to a group of substrates due to its 3d configuration of its active site that is compatible to specific substrate structures
30
property five enzyme
catalysed reaction is reversible
- enzymes can catalyse forward and reverse reactions
- direction of reaction depends on concentration of reactants and products
- enzymes catalyse reaction int eh direction of equilibrium
31
property six enzymes
enzymes activities are affected by multiple factors
- enzymes work best at optimal temperature and pH
- enzymes can be denatured at extreme pH or temperature
- if enzyme concentration is increased, the rate of enzyme reaction will increase
- increasing enzymatic activity by increasing substrate will eventually be limited by the amount of enzymes available
32
property seven enzyme
- enzyme rate of reaction increases as enzymes decrease activation energy of reaction
33
active site (hydrolase/enzyme)
- pockets on the surface of the eznyme which substrate can fit
- the amino acid r group that form the active site are arranged to interact specifically witht he substrate
34
activation energy definition
- energy required for the substance to react
- the greater the activation energy, the slower the rate of reaction
35
explanation of energy needed for product (reactant to product)
- compound y requires energy to convert into compound x
- the reaction takes place when compound y acquires enough activation energy from it surrounding to undergo the reaction
- energy may be provided by unusually energetic collision with other molecules
36
explanation of energy needed for product (product to reactant) ★
- the activation energy from the product (Y) to the reactant (x) -- reaction is more rare
- activation energies are always positive
-> total energy change for the energetically favourable reaction y right arrow x is energy c minus energy b a negative number
- energy barriers for specific reactions can be lowered by catalysts
- enzymes are effective catalysts because they greatly reduce the activation energy for the reactions they perform
37
lock and key hypothesis
substrate is a key whose shape is complementary to the enzyme/lock
- once products are formed, the product no longer fits into the active site and escapes into the surrounding medium, leaving the active site free to receive other substrates
38
pepsin
- protease efficient in cleaving peptide bonds between hydrophobic amino acids
- produced int he chief cells in the stomach
- digestive enzyme residing int eh acidic environment of the stomach
optimal pH of 2
39
salivary amylase
- amylase efficient in breaking down amylose molecules ot simpler substances
- produced by the salivary glands
- digestive enzyme residing in the neutral environment of the mouth
- optimal pH of 7
40
amoutn of substrate changed/product formed and time graph
- increase
- rate of reaction= change in amount of substra/reaction time
41
